IB Biology B2.2 Definitions
This page contains our IB Biology definitions for B2.2. By learning each one of these definitions, you will fully cover the content for IB Biology 'Further organelles'.
Chloroplast
Organelles in plant cells where light-dependent reactions of photosynthesis occur
Clathrin
A protein that forms a lattice around newly forming vesicles, playing an important role in vesicle formation
Cristae
Folds of the inner membrane in mitochondria, increasing the surface area for oxidative phosphorylation
endocytosis
Invagination of the plasma membrane around substances to form a vesicle that transports substances into the cell
exocytosis
Release of substances into the extra-cellular matrix through fusion of vesicles with the plasma membrane
Grana
Stacks of thylakoids that optimize light absorption and are distributed throughout the stroma
light absorption
The process by which light is absorbed by an organism for use in cellular processes
Matrix
The cytoplasm of the mitochondria, containing enzymes for the link reaction and Krebs cycle
Mitochondria
Organelles in cells where the link reaction, Krebs cycle, and oxidative phosphorylation occur, producing ATP
Nucleus
The organelle in eukaryotic cells that contains genetic material, controls the cell, and is bounded by a double nuclear membrane
Ribosomes
Organelles responsible for protein synthesis, found free within the cytoplasm and associated with the endoplasmic reticulum
Stroma
The chloroplast cytoplasm containing starch grains, lipid droplets, and enzymes for the light-independent reactions
Thylakoids
Internal membrane systems in chloroplasts that increase surface area for light-dependent reactions
Vesicles
Small membrane-bound sacs formed during exocytosis or endocytosis, transporting substances within and out of the cell
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